Ntimed is an alternative to net-misc/ntp. http://phk.freebsd.dk/time/20141221.html
0 releases on https://github.com/bsdphk/Ntimed
This is something I'm interested in. I've created the ebuild and related scripts in my overlay: https://github.com/titanofold/titanofold-gentoo-x86/tree/master/net-misc/ntimed